import time
scale = 10
print("------开始执行------")
for i in range(scale+1):
    a, b = '**' * i, '..' * (scale - i)
    c = (i/scale)*100
    print("%{:^3.0f}[{}->{}]".format(c, a, b))
    time.sleep(0.1)
print("------执行结束------")
